Advances in functionalized biodegradable biliary stents: From material design to clinical translation

Biliary stricture, primarily caused by inflammation, hepatobiliary and pancreatic malignancies and other pathological factors, often leads to impaired bile drainage and subsequent poor clinical outcomes. While biliary stent implantation has become a standard palliative and therapeutic intervention, conventional plastic and metal stents are limited by issues such as biofilm formation, epithelial hyperplasia, and the necessity for secondary removal surgery. The emergence of biodegradable stents offers a promising alternative by providing temporary mechanical support and controlled in vivo degradation, thereby eliminating the need for retrieval procedures. However, single-material stents often fail to address the complex and varied clinical demands, particularly in cases involving biliary fibrosis, infection, or malignancy. This review comprehensively summarizes recent advances in functionalized biodegradable biliary stents, referring to additional capabilities beyond their primary mechanical function, with a focus on material innovations and their enhanced functionalities such as anti-fibrotic, anti-tumor, antimicrobial, anti-corrosion, and visualizable properties. We also discuss integrated therapeutic strategies, such as drug-eluting systems and tissue-engineered scaffolds, alongside manufacturing breakthroughs like 3D printing. Furthermore, we also highlight the persistent translational challenges and preclinical limitations of current biodegradable stent technologies, while outlining promising directions for future research to bridge the gap between experimental development and clinical application.